Networking, internet and file transfer between macs

Here is the story. I haven't work with macs for a while due to financial reasons, but I'm happily (or so I thought) back now to a mac environment. I have a Macbook 13" (which is my old Computer) and a Macbook pro 15" (my new one). They are both 2.4 Ghz from mid last year's.Here are the issues I'm having trouble with:

1 Network the two mac wirelessly by creating a network which I called HomeMac through airport. Whilst I'm able to see the Macbook pro on the Macbook it does not happen the other way around. What can I do?

2 Connect both computer to the internet through a router which is connected to a surf Motorola modem (cable internet). Unfortunately, I only manage to connect one computer at a time because as it happens, when I do the network diagnostic to the one that doesn't connect (and follow the steps of turning each device off and on), I loose connection to the other. How can I do this?

3 Transferring files from my old Macbook to my newest Macbook pro using the migrant assistant. I spent like 2 hours waiting while it transfered the file, however when I went to see them I couldn't find them. I did though find an account under the user name of my ld computer, however each folder had a small red circle next to them and when I was to open them it told me that I didn't have enough privileges to access them. What did I do wrong?

Please please mac community, I would so appreciate your help on this one. I truly thought it was going to be (as always is with macs ) easy to do all of the above, but this is something I have never done in the past and so all actions have been rather tentative with unsuccessful results.